Control means for a conveyance



Oct. 3, 1961 H. w. KRAUs CONTROL MEANS FOR, A CONVEYANCE 7 Sheets-Sheet 1 Filed D60. 5, 1958 Get. 3, 1961 H. w. KRAUS 3,002,578

CONTROL MEANS FOR A CONVEYANCE Filed D60. 5, 1958 7 Sheets-Sheet 2 50 53 29 E as Oct. 3, 1961 H. w. KRAUs CONTROL MEANS FOR A CONVEYANCE 7 Sheets-Sheet 3 Filed Dec. 5, 1958 Oct. 3, 1961 H. w. KRA'U'S CONTROL MEANS FOR A CONVEYANCE 7 Sheets-Sheet 4 Filed D90. 5, 1958 IN V EN TOR. Hans MWfie/m Krau's Oct. 3, 1961 H. W. KRAUS CONTROL MEANS FOR A CONVEYANCE 7 Sheets-Sheet 5 Filed Dec. 5, 1958 IN V EN TOR.

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6w, ham 9 MM Oct. 3, 1961 H. w. KRAUS CONTROL MEANS FOR A CONVEYANCE 7 Sheets-Sheet 6 Filed Dec. 5, 1958 Oct. 3, 1961 H. w. KRAUs 3,002,578

CONTROL MEANS FOR A CONVEYANCE Filed Dec. 5, 1958 7 Sheets-Sheet '7 IN V EN TOR.

United States Patent 3,002,578 CONTROL MEANS FOR A CONVEYANCE Hans Wilhelm Kraiis, Jaegerstrasse 10, Buckeburg, Land Niedersachsen, Germany Filed Dec. 5, 1958, Ser. No. 778,457 8 Claims. (Cl. 180-8) This invention relates to a control device governing grouped means of load transport moving independently of one another. More specifically, it relates to a control mechanism for operating the movement of the legs of a conveyance, like a truck, which is equipped with striding legs rather than wheels. The device of the present invention is particularly adapted for use with the conveyance disclosed in my copending application Serial No. 700,592, now Patent No. 2,942,676, filed December 4, 1957. Such conveyances have a load carrying chassis having three or more legs adapted to lift the chassis and the load thereon from the ground and move it in any direction-forward, backwardor laterally. The legs resemble hydraulic jacks controlled to work in concert in lifting the chassis from the ground, moving it by tilting the legs in the desired direction and lowering the chassis once again to the ground. Such conveyances are useful in connection with heavy equipment such .as earth moving machines, cranes or mining conveyors and the like.

The primary object of the invention is to provide a control means which makes possible the coordination of the several legs of the conveyance to move the conv eyance in the direction and at the speed desired.

The problem to be solved by means of the invention may occur in connection with the transport of heavy loads, such as earth moving equipment which, because of its size, requires the application of several load carrying units. It is difiicult to coordinate the movement of the several load carrying units when driving round curves and especially when turning on the spot, because such movements require great differences in the direction and the speed of movement of the different units carrying the load.

By the present invention this problem has been solved by automatically coordinating the inter-adjustment of the groups among each other and the single members of each group in regard to the direction and speed of movement, that movement of the load takes place in the predeter; mined direction and speed.

This is achieved by exercising the control of the separate movements of the transport units or their members through a miniature device carrying out these or corresponding motions on a smaller scale and corresponding geometrically and in arrangement with the transport unit. The motions and rhythm of the control device can be effected by mechanical or electrical appliances giving controlling signals, such as cams, magnetic tape recorders and the like.

The invention can be realized by moving a miniature model of the transport units group carrying the load-and, when using striding feet a model of the separate striding feet themselves-through a plane joining the points of contact of these groups, which plane at any point of time also represents a model of the loaded group surface. During this process the separate members of the controlling device carry out the movements of the transporters and their members. The movements are then transferred to the separate transporters of the conveyance in a manner already known by means of remote power transmission and power amplifier appliances similar in principle to copying devices.

In the case of mechanical striding devices where a tended several groups of striding mechanisms must be ice used. In this case the load is taken over from one striding mechanism by another and the separate groups carry out movements phased in relation to each other. For each group of striding mechanisms there must then be a special controlling device. The separate controlling devices are then in mutually phased positions moved by the driven ca-m discs, whereby several control devices may be operated by the same cam discs, from which the movement of different parts of the circumference will then be derived.

Striding mechanisms with common striding foot surface areas are of practical use only if the ground is not too uneven. If the load is to be distributed evenly over all the principally vertical supports in a striding mechanism group in spite of unevenness of the ground this can better be achieved by separate striding feet movable in relation to each other. The lift of the striding feet can in this case be produced by allowing the striding foot on its down stroke to contact the ground very gently at first and then applying the power lift when lifting the load. In the case of hydraulic operation of the striding feet this could be secured by first filling the lifting cylinder of each principally vertical support quickly with oil under air pressure, after which, when a predetermined minimum pressure has been reached, a control valve is operated switching over to high pressure oil enabling the lift to take place with the necessary power. A permanently horizontal position of the load could be secured by using control valves operated by a pendulum which would control the filling of the lifting cylinders.

The invention is described in greater detail by certain examples of executions illustrated in FIGURES l to 8a.

FIGURE 1 gives a perspective view of a load equipped with striding mechanisms guided by the control device, the subject of this invention;

FIGURE 2 shows a plan view of the same arrangement, negotiating a curve;

FIGURE 3 shows a plan view of the same arrangement turning on the spot;

FIGURE 4 shows a diagrammatic side view of an arrangement for a control device;

FIGURE 4a shows the same arrangement seen from above;

FIGURE 5 shows diagrammatically a side view of the arrangement of a striding foot on the load;

IZFIGURE 5a shows the same arrangement seen from a ove;

FIGURE 6 shows a side view of an arrangement as it might be in practice and the coordination between the control device and the striding mechanism;

FIGURE 6a shows the same arrangement seen from above;

FIGURE 7 shows a side view of another form of the control device;

(FIGURE 7a shows the same arrangement seen from above;

FIGURE 8 shows a side view of a special form for the control device; and

. FIGURE 8a shows the same seen from above.

FIGURE 1 shows a load fitted with three striding feet 1. On each striding foot 1 is joined, through. a ball joint 16, a principally vertical support 2 which in turn, through a ball joint 12 at its upper end, is joined to a power-operated arm 5 which is arranged to swivel about a horizontal joint 3 on the load 11. By means of arm 5 the lifting motion of striding foot 1 is produced. The lateral motion of striding foot 1 is produced by two principally horizontal supports 3 and 4 linked to it at approximately right angles through a double ball joint, and whose outer ends are linked to power-operated arms 6 and 7 through ball joints 13 and 14. The arms .6 and] are attachedto load 11 by vertical swivel joints 9 and 10. By such an arrangement the striding foot 1 can be given a motion in any direction required. When moving straight forward the striding feet will simultaneously make the same am plitude of movement. It is, however,-even in this case dif-. ficult to coordinate the movements of the arms'S, 6 and 7 in relation to each other so that the desired movements of the striding foot in relation to the load 11 .will occur. This problem is, however, solved bythe control device, the subject of this invention.

If travel of the load 11 round a curve is required, as shown in FIGURE 2, the separate striding feet must carry out different motions in direction and amplitude. This problem also has been solved by the invented control deyice. The travel round a curve can be carried out either with the load retaining its original direction or with the direction of the load moving round the curve in the manner of a wheeled vehicle which turns tangentially to the curve being negotiated. In either case the movements of the separate striding feet will have to be diiferent, which, however, can also be accomplished by the control device, the subject of this invention. The control device can also rotate the load 11 on the spot as shown in FIGURE 3.

The control device represented diagrammatically in FIGURES 4 and 4a contains mainly a baseplate 18 to which models of the principally vertical supports 2, described in the control device as 2, are linked in a geometrically similar manner to the ball joints 16 between the striding foot 1 and the support 2 in the full scale part. The support 2 is thus connected to the baseplate 18 through a ball joint 16'. In a corresponding manner the other supports of the corresponding separate striding feet are linked to the baseplate 18. The two other principally vertical supports are indicated by the numbers 2" and 2". The upper end of the vertical support 2 is, corresponding to the full scale part, connected by a ball joint 12 to an arm which is held by a horizontal linkS' in a stationary bearing on the housing 50 of the control device. When the base plate 18 moves up and down the arm 5 will accordingly carry out a vertical swivel movement.

The baseplate 18 rests upon a turntable 21 which is carried in a rotating ring 34on a rising and falling frame 33. The turntable 21 can be set inany direction in the horizontal plane by means of a rack and a pinion 22 held on a shaft 23 which is turned by hand. The shaft 23 is held in a fixed bearing on the housing 58 of the device. The amount of the turn can be read off a rotatable scale 24 connected with the upper end of the shaft 23.

Since the arrangement consisting of the frame 33, the turntable 21 and the baseplate 18 are vertically movable it follows that with a vertically immovable scale 24 the shaft 23 must be adjustable for length.

Independently of the up and down movement and of the turning movement, the baseplate 18 must carry out a reciprocating movement in the horizontal plane. This reciprocating movement corresponds to the length of stride.

Furthermore, the baseplate 18 must, independently of the up and down movement and the reciprocating movement, also be able to carry out a pendulum movement corresponding to the pendulum movement of the striding feet when, for instance, turning on the spot.

To be able to make all these movements independently of one another the frame 33 is movable through a parallelogram guiding arrangement in the up and down direction but is connected with the housing of the device in such a way that it cannot turn. This parallelogram guide consists of a double-arm angle lever 35 and a treble arm lever 36, the approximately vertical arms of which are connected with one another by a coupling rod 37. The up and down movement of the frame 33 is brought about by a rod 38 which is attached to the outer end of the treble arm 'lever and operates in conjunction with a cam 39. The cam 39 has a lifting curve extending over approximately a half circle so that in the course of approximately a half revolution the frame 33 is lifted and during the other half revolution it is lowered in relation to the housing 50 of the de- 4 vice. The reciprocal motion of the baseplate 18 in the horizontal plane is caused through a single arm lever 25 and a double arm angle lever 26 which through the guides 27 and 28 are connected with a circular bearing ring 20. The baseplate 18 can be turned round its vertical axis about the bearing ring 20.

The baseplate 18 is accordingly horizontally rotatable in relation to the turntable 21 but only in the direction predetermined by the position of the turntable 21 since the bearing ring 20 cannot rotate with respect to the turntable '21. The baseplate 18 is, however, in whichever position it is vertically disposed, able to oscillate about the bearing ring 20 in the sense of a pendulum motion. The guides 51 and 52 of the parallelogram linkage limit the angular rotation of the baseplate, as explained below.

The horizontal reciprocal motion is produced by upward and downward movement of a connecting rod 30 which at its upper end is connected through a ball joint 29 with the lower end of the angle lever 26. The lower end of the coupling rod 30 is also connected by a ball joint 31 with an angle lever 32 which is fastened by means of a horizontal joint to the rising and falling frame 33.

To make the movement of the angle lever 32 independent of the rising and falling movement of frame 33, the lower end of the angle lever 32 is connected by a sufiiciently long coupling rod 40 with a second double-arm angle lever 41 which is connected by a horizontal joint with the housing 50. The other end of this double arm angle lever 41 is connected by a joint with a rod 42, the lower end of which operates through a roller against a cam .disc 43. V The cam disc 43 has an approximately heart-shaped circumference and serves to control the movement and length of the stride in a horizontal direction.

In FIGURES 6 and 6a the two halves of the hear-tshaped curve are symmetric as in a mirror. Thus, the transporting motion and the idling (return) motion of the striding foot are of the same form. The heartshaped curve may, however, also be formed unsymmetrically in such a manner that, the idling motion is quicker than the transporting motion.

' Because the joints 28 and 31 at the ends of the 0on necting rod 30 take the form of ball joints, the turn table 21 can be turned in relation to the lever system 32, 40, 41, 42 without any reaction on the reciprocating motion of'the baseplate 18. The connecting rod 30 should be located approximately vertically in the central axis of the turntable 21.

The pendulum motion of the baseplate 18 about the bearing ring 20 in the horizontal plane is accomplished by the arrangement not shown in FIGURE 4 but shown in FIGURE 4a. The baseplate 18 together with the guides 51 and 52 and the treble'arm angle lever 49 forms a parallelogram. The pivot of the angle lever 49 is, however, not fixed but is in its turn connected through a parallelogram consisting of the central arm of the treble arm angle lever 49, the guides 47 and 48 and a double arm angle lever 46 with a rod 45 operating in conjunction with an eccentric cam 44. The vertical swivel joint of the double arm angle lever 46 is bedded on the housing 50. In the same joint the guide 47 is also bedded. By this arrangement the pendulum or oscillatory motion of the baseplate 18 about the plate 20 can be made independent of a reciprocating motion of the plate 20 and of the baseplate 18.

The cams 39, 43 and 44 consist of cam tracks of different lift (contour) arranged beside one another on the same shaft, as may be seen in FIGURES 6 and 6a. This enables the amount of lift and the length of stride of the conveyance to be adjusted as required. Cam 39 regulatesthe lift, cam 43 the stride, and cam 44 the turning of the conveyance. A cam follower .139, 143, 144 rides on the face. of each cam and througha linkagelimparts the desired motion for steering the model and, in turn, the conveyance. The cam 44 is SO formed that in its central range there is no eccentricity whilst toward both its ends the eccentricity, displaced by 180 one against the other, rises. As the earns 39, 43 and 44 are placed on the same shaft the direction of turning of the load to the right or left can be chosen at will, whereby in the central position of cam 44 no turning motion will occur, even when motor 61 is turning shaft 60. With the follower at central position the conveyance walks straight ahead.

The longitudinal displacements of earns 39, 43 and 44 with respect to their followers can be accomplished independently of each other in a manner already known, by the use of grooved rings 62, 63 and 64, in cooperation with levers lllZ disposed therein as shown in FIG- URE 6. A crank r163 connecting to the lever permits adjusting for length of stride, lift and turning motion. The common shaft 66 of the cams is driven by a motor 61 which for convenience should have a variable speed or gear to be able to regulate the stride frequency.

As may be seen from FIGURES 5 and 5a and also FIGURES 6 and 6a, in the construction being considered the control movement is transmitted to the separate striding mechanisms by means of wire ropes. In the illustration the transmission to a single striding mechanism through wire ropes I52, 157 and 158 is shown.

Of course, instead of rope transmission other known types of transmission, for instance electrical rotating impulse givers and receivers or hydraulic transmissions may be used. In the transmission by ropes shown, which is the easiest way of illustrating the action, the ropes have been attached at each end over a pulley on the controlling device and on the striding mechanism, whereby the striding foot shown has three ropes with their pulleys for the three components of movement.

The mode of action is shown on the device for the transfer of'the lift motion. The vertical swivelling mo tion of the arm 5' on the control device is transmitted from the pulley 17 linked to the arm, through the rope 152 to a corresponding pulley 17 in the striding mechanism. The rope 152 is in this connection held under tension by a tension spring 1? which bears on a lever 54 fixed to the pulley. On the same shaft as that of the pulley 17 but swivellable in relation to it there is, corresponding to the control device, fitted an arm 5 which is connected through a ball joint 12 with the upper end of the principally vertical support 2.and causes its 11fting motion.

Arm 5 carries a sprocket segment 53 which by means of a motor-driven pinion 98 can be swung together with arm 5. The control of the motor is through contactors located on the prolongation of lever 54 which, when the lever 54 swivels in relation to the sprocket segment 53, makes contact with contactors 75 and 76 located on the latter. In the' central position of lever 54 these contactors do not touch the contactors 75 and 76. If how ever, a control movement from the control device issues through the rope'152, then the contact lever 54 will be-laid over on one of the contacts 75 or 76 according to the direction in which the arm is guided. When contact is made the motor turning the pinion 98 will operate in the desired direction of rotation and will remain switched on until, by turning arm 5 with the segment 53, the contactors again come apart, i.e. when 1ever54 regains its central position between contactors 75 and 76.

In the ropes 152, 57 and 58 a tension spring, not otherwise shown, is inserted under such tension that its pull is stronger than that of spring 19. This avoids tearing of the ropes when the contactors on lever 54 strike the contactors 75 before the arm 5 has been lowered.

By this arrangement, which is only given as an ex-' ample, it is easy to transfer the desired turning motion from the control device to the striding mechanism.

The control of the movements of the principally horizontal supports 3 and 4 is carried out in a similar way by the rope pulleys 55 and 56 through ropes 57 and 58 acting on the corresponding pulleys 55 and 56 in the striding mechanism, whereby the arms 6 and 7 are swivelled horizontally. I

In FIGURES 7 and 7a a control device is shown di agrammatically, with the help of which the control movements are obtained in another way. In common with the control device shown in FIGURES 4, 4a, 6 and 6a, it has a baseplate corresponding to the ground surface which in relation to an arrangement of'points in space which correspond to the points where the striding feet are linked to the load, carries out the required relative movements. In FIGURE 7 the baseplate 68 is carried on a cross slide 67 in the housing frame 50, turnable horizontally about a pivot 66. The cross slide 67 permits a reciprocating movement of the baseplate 68 in relation to the pivot 66 in any direction but prevents the baseplate 68 from turning in relation to the pivot 66.

Thereciprocating motion of the baseplate 66in the desired direction and amplitude is given through a pantograph type of parallelogram arrangement consisting of the outer guides 69 and 71 and the two inner and shorter guides 73 and 74. The two inner guides 73 and 74 are fixed to the housing 56 by a swivel joint. The outer ends of the outside guides are at one end linked to a point 70 on the baseplate 68, for instance at the edge of the baseplate, and at the other end, at the end point 76, connected to a straight guide 75 which can be pivoted in the horizontal plane and is adjustable. The baseplate 68 will then carry out reciprocal movements in relation to the movement of the end point 76 as controlled by the straight guide.

The turning of the straight guide in the horizontal plane is carried out by means of a .disc 72, which should suitably be provided with graduations, adjustable about a vertical pivot 77. To be able to carry out the straight movement of the end point 76 in the guide 75 independently of this turning motion the movement which causes the reciprocating motion is conducted from outside in a vertical direction through the hollow pivot 77 and trans ferred through a vertical tooth rack 78 via a gear wheel 79 to a horizontal tooth rack Sil which slides in the guide 75 and which is connected with the end point 7 6.

By means of the straight guide 75 the reciprocating motion of the baseplate 78 corresponding to the desired size and direction of the stride is made possible.

The lifting motion is initiated in the control device by the upper link points of the miniature striding foot model being linked to a supporting plane 81 which, according to the lift desired, is moved up and down on a vertical rod 82, held in a fixed bearing 88, by means of the lifting cams. This avoids the difficulties which would arise with the design according to FIGURES 4, 4a, 6 and 6a as a result of the simultaneous lifting movement of the members serving the reciprocating and turning motions of the baseplate 18.

If, for the transfer (transmission) of the control motion to the striding mechanism, instead of a rope transmission an electric transmission is used, for instance by means of rotary impulse givers 83, and 86, there will be no difliculties in transmission caused by the up and down motion of the supporting plane.

The swinging pendulum motion of the baseplate 68 in relation to the supporting plane 81, as required when. the load is turned on the spot, can be initiated (inducted) in the control device in various ways. For example, as shown in FIGURE 7, the lower part of the arrangement with the cross slide guide 67 and the baseplate 68 are turned to and fro about the pin 66 through a cam-guided lever 87, whilst the guide rod 82 is connected with the supporting plane 81 swivelling in the bearing 88, or else the lower part of the cross slide guide 67, eliminating the pinion 66, is directly connected with the housing 50 and the swinging pendulum motion is transferred to the sup- 7 porting plane 81 by the cam, the guide rod 82 being held swivelling in the bearing 88.

Of course, any other suitable kinematic combination of adjustable members can be used, which will give the striding feet the required movement in relation to the load, corresponding to the motion of the baseplate 68 in relation to the supporting plane 81.

The base plate 68, of course, simulates the position of the ground relative to the legs of the striding mechanism and actuates all of the legs simultaneously.

Proceeding from the principle of the free choice of lengths and if necessary also angles in the geometric addition of lengths, such arrangements can easily be found. With the infinite number of the available variations it is not possible to give anything like an exhaustive description of them.

It is not absolutely necessary that the arrangement of the striding feet in space shall correspond in perfect geometrical proportion to the arrangement of the full scale feet. To be able to reduce the dimensions of the control device it is advantageous to have the distances between the model striding feet in the control device smaller than the proportionate distance in the full scale arrangement. To obtain in spite of this the correct curve motion of the link points 16 of the supports 2' on the supporting plane, curve guides whose bending center does not coincide with the central point of the supporting plane but is at a greater distance, can be used.

An example of such an execution is shown in FIG- URES 8 and 8a which represents a corresponding adaptation of the arrangement shown in FIGURES 4 and 4a. The support 2' is in this case not linked immediately at the corner of the triangular baseplate 18, but via the ball joint 16' to a slide block 91, guided in a radial slot in the baseplate 18. In the lower half of FIGURE 8a the guiding of the sliding block 91 in the slot 90 is again shown separately. The bearing ring 20 is extended outwards by a plate 89 which is provided with curved slots 92 into which a pin 97 underneath the sliding block 91 projects.

The center of bending of the curved slot 92 does not coincide with the center 93 of the bearing ring 20 and the baseplate 18 but lies about twice as far away in point 94. In the event of relative swivelling motions of the baseplate 18 in relation to the bearing ring 20, as they would occur when turning on the spot, the foot point 16' of the support 2' would carry out the same circular motion as if the foot point 16' were at approximately twice the distance away from the central point 93 of the bearing ring 20.

This device can be employed for all the striding feet and thus it is possible to reduce the width of the control device by about half.

The invention is explained by means of an example of execution and use of a controllable striding foot. As mentioned at the beginning the usefulness of the control device according to the invention is not limited tosuch striding mechanism arrangements but can also be used for all kinds of transport units operating in groups, such as those employing a number of tracked vehicles.

Also the means of transmitting the control motion to the load carrying appliance can be chosen as desired. Suitable transmissions for this purpose are, for instance, mechanical, electrical, pneumatic or hydraulic transmissions. Also the movement of the striding feet can be other than that shown, for instance by hydraulic or pneumatic cylinders with pistons, by hydraulic motors, control gear, screw jacks, rack jacks, etc. whereby these appliances with suitable movements are reproduced on a smaller scale in the control device without, however, having to operate in exactly the same manner. Thus it is possible, for instance, to represent a displacement of a hydraulic cylinder with a piston by means of a sliding contactor on an electric resistance, which in its simplest form can be formed as a straight line and so with alteration of the contactor potential (voltage) control the filling of the hydraulic cylinder.

The control device can either be mounted on the load itself so that it carries out the movements together with the load or it can be installed in a separate fixed control cabin together with other control appliances for other loads. In the latter case electric transmission of the control signals would be suitable. It is also possible to transmit the control signals by radio.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A control device for a movable carrying unit comprising a housing, a miniature model having the geometrical configuration of said unit within said housing and supported on a plate-like surface, support means secured to said housing on which said plate-like surface is mounted for vertical and horizontal movement to reproduce the movements of said unit in said model, means for actuating said surface to produce the motion desired and means for coupling the movement of said model with said carrying unit.

2. The device of claim 1 wherein said actuating means comprises cams.

3. The device of claim 2 wherein said cams are replaceable to change the amplitude and duration of the motion imparted to said model.

4. A control device for a load carrying conveyance having a supporting base mounted on a plurality of striding mechanisms in contact with the ground comprising a housing, a miniature reproduction of said conveyance within said housing including a baseplate simulating the ground and principal support levers connected thereto simulating said striding mechanisms, support means secured to said housing on which said baseplate is mounted for vertical, horizontal and rotatable movement, actuating members connecting to said support means and said base plate to move said base plate and the levers connected thereto in accordance with a predetermined series of movements to be imparted to said striding mechanism, means for amplifying the force produced by the motion of said levers, and means for transmitting said amplified force from each said lever to the corresponding element in said striding mechanism.

5. The control device of claim 4 in which said baseplate is mounted for rotary motion on a ring, which in turn is mounted on a turntable for imparting lifting motion thereto.

6. The control device of claim 4 in which said support means includes a ring on Which said base plate is rotatably mounted, a turntable mounted for movement in a single predetermined path, a first parallelogram linkage interposed between said ring and said turntable for imparting lifting motion thereto, a second parallelogram linkage for. simultaneously oscillating said baseplate on said ring and a rod disposed substantially in the axial direction of the turntable, said rod receiving its motion from a cam.

7. The control device of claim 4 wherein said support means includes a grooved member which permits the plate to move in a single predetermined path, said support being pivotally mounted on the housing, and said actuating members include a parallelogram linkage interposed between said baseplate and means for actuating same.

8. A control device for a load carrying conveyance having a supporting base mounted on a plurality of striding mechanisms, each striding mechanism comprising a main lever and two struts pivotally connected thereto having the other ends thereof pivotally secured to said base, said device comprising a miniature reproduction of said conveyance including a baseplate corresponding to. said support base, and a plurality of miniature levers pivotally connected thereto simulating said main lever of ecah of the stn'ding mechanisms, means for actuating said baseplate with a swivelling and lifting motion to impart a walking motion to said miniature levers and means for amplifying and transmitting said motion to said striding mechanism, whereby said striding mechanism is given the motion imparted to the miniature reproduction.

References Cited in the file of this patent UNITED STATES PATENTS Cameron Nov. 2, 1948 FOREIGN PATENTS France June 30, 1954 Germany Oct. 11, 1954 

